Emergency power shutdown management system

ABSTRACT

An emergency power shutdown management system (EPSMS) comprises a programmable logic controller (PLC), relays coupled to the outputs of the PLC for shutting down electrically operated equipment, and indicators for indicating the status of the EPSMS and the controlled equipment. The PLC receives input signals from a fire control panel including a 2 nd  alarm signal which is generated after the fire control panel has detected smoke, fire or an explosion with two or more detectors and a system discharge signal which is generated when the fire control panel triggers fire sprinklers or the release of other fire or explosion suppression agents. The PLC also receives an emergency power off (EPO) signal from an EPO switch which is activated to immediately shut down all electrically operated equipment and power distribution units in a protected area. The indicators include a 2 nd  alarm indicator for indicating a 2 nd  alarm activation; a system discharge indicator for indicating a discharge of fire or explosion suppression agents; and an emergency power off indicator for indicating an emergency power off situation. The relays include 2 nd  alarm equipment relays coupled with a first set of equipment; system discharge relays coupled with a second set of equipment; and shunt trip relays coupled with a third set of equipment. All of the components of the EPSMS are housed within a single cabinet for consolidating the control and alert functions of the EPSMS in a single location.

RELATED APPLICATION

The present application is a continuation application and claimspriority benefit, with regard to all common subject matter, of anearlier-filed U.S. nonprovisional patent application titled “EMERGENCYPOWER SHUTDOWN MANAGEMENT SYSTEM” Ser. No. 11/257,283, filed Oct. 24,2005. The identified earlier-filed application is hereby incorporated byreference into the present application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an emergency power shutdown managementsystem. More particularly, the invention relates to such a system thatconsolidates, controls, and monitors the power off circuits for a roomor other zone protected by a fire or explosion protection system.

2. Description of the Prior Art

Many buildings, factories, and other facilities include rooms or otherzones protected by fire and/or explosion suppression equipment. Beforeand during operation of such suppression equipment, it is necessary tocontrol and shut down certain electrically operated equipment. Forexample, before discharge of a fire or explosion suppression agent intoa room, it is desirable to first shut down air handling units, exhaustfans, etc. to prevent interference with the dispersion of thesuppression agent. It is also necessary to shut off all power and powerdistribution units to protect firefighters and other persons who may bein the room.

Emergency power-off controls are often provided for these purposes.Unfortunately most emergency power off controls are afterthoughts. Theyare designed, installed, and tested in the field at the end of a projectin order to meet code minimum requirements and get the job signed off.Consequently, most jobs end up with a “decentralized” emergency poweroff system usually comprised of relays located in j-boxes scatteredabout the room, sub floor, and/or above ceilings; and unidentified andunmonitored circuit breakers that feed power to shunt-trip breakers andrelays. Moreover, these systems are typically undocumented—no wiringdiagrams, location of devices, and intended sequence of operation.Additionally, there are typically no easy ways to defeat these systemsduring routine maintenance. Emergency power off controls installed inthis fashion are also subject to some troubling ongoing operationalissues. For example, such systems can be unreliable in that wires can bedisconnected or shunt-trip power circuits turned off rendering thecontrols useless with no trouble alarm or notification to users.Similarly, since there are no simple ways to disable these controls,accidental activation and thus accidental equipment shutdown can anddoes occur. Due to lack of documentation, changes or troubleshooting iscumbersome and costly.

There is therefore a need for an improved emergency power shutdownmanagement system that overcomes the limitations of the prior art. Moreparticularly, there is a need for a system that more effectivelyconsolidates, controls, and monitors the power off circuits for a roomor zone protected by a fire or explosion protection system.

SUMMARY OF THE INVENTION

The present invention solves the above-described problems and provides adistinct advance in the art of emergency power shutdown managementsystems. More particularly, the present invention provides a system thatmore effectively consolidates, controls, and monitors the power offcircuits for a room or other zone.

The present invention solves the above-referenced operational problemsby providing an emergency power shutdown management system (EPSMS) whosecontrols are consolidated in a single cabinet and that is manufacturedand tested off site. The system is programmed to receive input signalsfrom a fire control panel and/or other input signal sources and to shutdown specified electrically-operated equipment in a manner that bestassists the suppression of a fire or explosion and protects people andassets in the protected area. The system includes superior monitoringcapabilities with local visual and audible annunciation and internalrelays which can be remotely monitored.

One embodiment of the EPSMS comprises a programmable logic controller(PLC), a plurality of relays coupled to the outputs of the PLC forshutting down certain electrically operated equipment, and a pluralityof indicators for indicating the status of the EPSMS and the controlledequipment. The PLC receives input signals from a fire control panelincluding a 2^(nd) alarm signal which is generated after the firecontrol panel has detected smoke, fire or an explosion with two or moredetectors and a system discharge signal which is generated when the firecontrol panel triggers fire sprinklers or the release of other fire orexplosion suppression agents. The PLC may also receive an emergencypower off (EPO) signal from an EPO switch which may be activated toimmediately shut down all electrically operated equipment and powerdistribution units in a protected area.

The indicators preferably include a 2^(nd) alarm indicator forindicating a 2^(nd) alarm activation; a system discharge indicator forindicating a discharge of fire or explosion suppression agents; and anemergency power off indicator for indicating an emergency power offsituation. The relays preferably include a plurality of 2^(nd) alarmequipment relays coupled with a first set of equipment; a plurality ofsystem discharge relays coupled with a second set of equipment; and aplurality of shunt trip relays coupled with a third set of equipment.Importantly, all of the components of the EPSMS are housed within asingle cabinet for consolidating the control and alert functions of theEPSMS in a single location.

In operation, the PLC activates the 2^(nd) alarm indicator and the2^(nd) alarm equipment relays upon receipt of a 2^(nd) alarm signal fromthe fire control panel. The 2^(nd) alarm relays then shut down the firstset of equipment. The PLC activates the system discharge indicator andthe system discharge relays upon receipt of a system discharge signalfrom the fire control panel. The system discharge relays then shut downthe second set of equipment. The PLC activates the emergency power offindicator, the 2^(nd) alarm equipment relays, the system dischargerelays, and the shunt trip relays upon receipt of an emergency power offsignal from an emergency power off switch. The relays then shut down thefirst, second, and third sets of equipment.

These and other important aspects of the present invention are describedmore fully in the detailed description below.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A preferred embodiment of the present invention is described in detailbelow with reference to the attached drawing figures, wherein:

FIG. 1 is an elevational view of an emergency power shutdown managementsystem constructed in accordance with a preferred embodiment of thepresent invention.

FIG. 2 is an elevational view of the emergency power shutdown managementsystem of FIG. 1 with its front door opened to show internal components.

FIG. 3 is a schematic diagram of the emergency power shutdown managementsystem of FIG. 1 shown operatively coupled with various input signalsources and controlled devices.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An EPSMS 10 constructed in accordance with a preferred embodiment of thepresent invention is shown in the drawing figures. As illustrated inFIG. 3, the EPSMS 10 may be coupled with various input signal sources,controlled devices, and monitoring devices for consolidating,controlling, and monitoring the shut-down of the controlled devices. Forexample, the EPSMS may receive input signals from a fire control panel12, a clean agent control panel 14, and an emergency power off (EPO)switch or button 16. The controlled devices may include a fire/smokedamper 18, one or more electrically operated door holders 20, an exhaustfan 22, an uninterruptible power supply (UPS) 24, equipment connected toone or more shunt trip breakers 26, and an air conditioning unit 28. Themonitoring devices may include a maintenance override beacon 30 and oneor more remote or outside monitoring stations 32. These are just some ofthe examples of the devices which can be coupled with the EPSMS, as thepresent invention can be used with other input signal sources,controlled devices, and monitoring devices without departing from thescope of the claims.

The fire control panel 12 monitors fire or explosion detection equipmentsuch as smoke detectors in a room or zone and provides a 2^(nd) alarmsignal to the EPSMS 10 upon detection of smoke, fire or an explosion byat least two of the detectors. The fire control panel 12 also starts atime delay countdown, such as a 30 second countdown, after receivingsignals from two or more detectors and then triggers sprinklers, rupturediscs or other devices to release fire or explosion suppression agentsinto the room or zone after the time delay countdown. At the same time,the fire control panel 12 provides a system discharge signal to theEPSMS 10.

The emergency power off (EPO) switch 16 may be activated to immediatelydisconnect power to all electrically operated equipment in the room orzone and to shut down or disconnect all power delivery equipment for theroom or zone. The EPO switch 16 also provides an EPO signal to the EPSMS10 when activated. The EPO switch is preferably a dual action keyedlatching type switch. The switch may labeled as follows:

-   -   Emergency Power Shutdown    -   This EPO switch is connected to an Emergency Power Shutdown        Management System (EPSMS) and can be overridden for maintenance        purposes.

As best illustrated in FIGS. 1 and 2, the EPSMS 10 includes one or moreprogrammable logic controllers (PLCs) 34 or other computing devices forreceiving the input signals from the fire control panel 12, EPO switch16 or any other input signal sources; a plurality of relays 36 coupledbetween the outputs of the PLC and the controlled equipment for shuttingdown the controlled equipment; a plurality of visual and/or audibleindicators 38 for indicating the status of the EPSMS 10 and thecontrolled equipment; and one or more control buttons or switches 39 forcontrolling certain functions of the EPSMS 10. These components are allconveniently housed within a single enclosure 40 for consolidating theshutdown of the controlled equipment.

The programmable logic controllers (PLCs) 34 may be Cutler-Hammer EatonEZ intelligent relay EZ 719-AC-RCX devices or any equivalent device. ThePLCs may also be replaced with other computing or logic devices.

The relays 36 may be any conventional relays such as N.O. and N.C.Cutler-Hammer C383RLDG intelligent process interface single type polesrated at 6 AMP 120 VAC. The relays 36 preferably include 2^(nd) alarmequipment relays 36 a for shutting down a first set of controlledequipment and system discharge relays 36 b for shutting down a secondset of controlled equipment. The first set of equipment may include thefire smoke dampers 18, magnetic door holders 20, exhaust fans 22, andthe AC or other HVAC equipment 28. The second set of equipment mayinclude the uninterruptible power supply units 24, power distributionunits, and other power protection devices.

The EPSMS 10 also preferably includes one or more shunt trip relays 42for shutting down a third set of controlled equipment connected toassociated shunt trip circuit breakers. The third set of controlledequipment may include some or all of the second set of equipment and/orother equipment which could cause electrical shock or electrocution to aperson.

The visual indicators 38 are preferably LEDs such as Cutler-Hammer E22H,full voltage, flush type LEDs rated at 120 VAC. However, other types ofvisual indicators may be used without departing from the scope of thepresent invention. As best illustrated in FIG. 1, the visual indicators38 preferably include a 2^(nd) alarm indicator 44 for indicating the2^(nd) alarm activation; a system discharge indicator 46 for indicatingthe discharge of fire or explosion suppression agents; and an EPOindicator 48 for indicating an emergency power off situation. The EPSMS10 may also include a power-on indicator 50 and two key switchindicators 52, 54.

The control buttons or switches 39 preferably include a lamp test button56 and a maintenance override key switch 58. The lamp test button 56 maybe any depressible or moveable button or switch such as a momentary redtest switch Cutler-Hammer E22P2A. The keyed override switch 58 disablesthe EPSMS 10, preventing it from shutting any equipment down regardlessof any input signals the EPSMS receives. The maintenance override keyswitch 58 can be any switch such as a two position Cutler-Hammer E33K53.

The visual indicators 38 also include the notification beacon 30 foralerting nearby persons when the EPSMS 10 is switched to the maintenancemode. The beacon 30 is preferably located a minimum of three feet abovethe EPSMS panel 10 and is be powered from the EPSMS control panel. Thebeacon 30 is activated when the maintenance override key switch is inthe override (maintenance) position.

The enclosure 40 is preferably a NEMA-1 rated enclosure capable of beingsurface or flush mounted with a swing door and key lock. The enclosuremay be constructed of any suitable material such as 18-gauge or greatersteel and may be powder coated red inside and out. All components of theEPSMS 10 are preferably furnished in one enclosure.

The EPSMS 10 is connected to a suitable source of power such as a 120VAC electricity source. Input power to the enclosure is protected by abreaker or fuse such as an internally mounted Cutler-Hammer 120 VAC10-amp circuit breaker.

The PLCs 34, relays 30, indicators 38, and buttons and switches 39 areinterconnected by wiring such as 16 gauge THHN stranded color blackwiring. All wire is routed in PANDUIT base duct slotted wall PanduitFIX2LG6 and covered with Panduit C1LG6. The EPSMS 10 may also includeappropriate terminal blocks such as Cutler-Hammer screw type singlelevel terminal blocks numbered with Cutler-Hammer identification labels.

All labels on the exterior of the enclosure 40 are preferably blackplastic with white engraved letters, a minimum of ½″ high. All labelsinside the enclosure are preferably P-Touch style. All relays and LEDsare labeled for their function. All labels coordinate with a wiringschematic and wiring diagram, a copy of which and sequence of operationis furnished and installed inside the enclosure.

Operation

The EPSMS 10 maybe installed and operated in any room, zone or otherarea which is protected by a fire or explosion control system. The EPSMS10 is preferably assembled and bench tested to verify proper operationprior to delivery to the job site. In normal operation, the power-on LED50 is illuminated, the keyed switch 58 is in the normal position, andthe key switch normal LED 52 is illuminated. All other indicators areturned off.

When the fire control panel 12 detects fire, smoke, or an explosion withat least two detectors, it generates a 2^(nd) alarm signal and sends itto an input of the PLC 34. The PLC 34 activates the 2^(nd) alarmindicator 44 and the 2^(nd) alarm equipment relays 36 a upon receipt ofthe 2^(nd) alarm signal. The relays 36 a then shut down the first set ofequipment described above to prepare the protected room or zone for theimminent dispersion of fire or explosion suppression agents into theroom or zone.

After the fire control panel 12 has completed the time delay countdowndescribed above, it generates a system discharge signal and sends it toan input of the PLC 34. The PLC activates the system discharge indicator46 and the system discharge relays 36 b upon receipt of the systemdischarge signal. The relays 36 b then shut down the second set ofequipment described above to prevent equipment damage and shock hazardsdue to release of the suppression agents.

Whenever a person activates the EPO switch, an EPO signal is sent to aninput of the PLC 34. The EPO switch may be activated by a person, forexample, when another person accidentally contacts a short circuit orother electrical hazard and is in danger of being electrocuted. Uponreceipt of the EPO signal, the PLC activates the emergency power offindicator 48, the 2^(nd) alarm equipment relays 36 a, the systemdischarge relays 36 b, and the shunt trip relays 42. The relays 36 a, 36b, and 42 then shut down the first, second, and third sets of equipment.The shunt trip relays 42 are preferably only activated for five secondsto prevent electrical damage to the coils of the associated shunt tripbreakers.

When the maintenance override key switch 58 is placed in the overrideposition, the key switch override lamp 54 is illuminated and the keyswitch normal lamp 52 is extinguished. The second alarm and dischargeshutdown relays 36 a, 36 b remain in normal position and cannot beenergized regardless of any input signal received by the PLC 34. Whenthe EPSMS 10 is in override, if any input signal is received, theappropriate second alarm LED 44, discharge LED 46 and/or EPO LED 48 isilluminated, but no equipment is shut down.

The EPSMS 10 also preferably includes a system trouble relay 60 which isactivated when the maintenance override switch 58 is in the overrideposition to send an appropriate warning signal to the outside or remotemonitoring station 32. The maintenance notification beacon 30 is alsoilluminated. The system trouble relay is also activated if the EPSMS isdisconnected from power.

When the lamp test button 56 is pressed, all lamps on the front of theEPSMS control panel illuminate for testing purposes. The lamps return totheir normal condition when the lamp test button is released.

Although the invention has been described with reference to thepreferred embodiment illustrated in the attached drawing figures, it isnoted that equivalents may be employed and substitutions made hereinwithout departing from the scope of the invention as recited in theclaims.

1. A power shut-down management system for use with a fire control panelfor consolidating, controlling, and monitoring the shut-down ofelectrically powered equipment, the system comprising: an alarmindicator for indicating an alarm activation; a discharge indicator forindicating a discharge of fire or explosion suppression agents; aplurality of alarm equipment relays coupled with a first set ofequipment; a plurality of discharge relays coupled with a second set ofequipment; a logic device programmed to activate the alarm indicator andthe alarm equipment relays upon receipt of an alarm signal from the firecontrol panel to indicate the alarm activation and to shut down thefirst set of equipment; and activate the discharge indicator and thedischarge relays upon receipt of a discharge signal from the firecontrol panel to indicate the discharge of fire or explosion suppressionagents and to shut down the second set of equipment; and a cabinet forhousing the alarm indicator, the discharge indicator, the alarmequipment relays, the discharge relays, and the logic device.
 2. Thesystem as set forth in claim 1, further including an emergency power offindicator for indicating an emergency power off situation and an audiblealert for audibly indicating the emergency power off situation.
 3. Thesystem as set forth in claim 1, the first set of equipment beingselected from the group consisting of air handling units, fire smokedampers, exhaust fans, and magnetic door holders.
 4. The system as setforth in claim 1, the second set of equipment being selected from thegroup consisting of uninterruptible power supply units, powerdistribution units, and other power protection devices.
 5. The system asset forth in claim 1, further including a maintenance override keyswitch having a normal position and a maintenance position, a key switchnormal indicator, a key switch override indicator, a pair of troublerelays, and a notification beacon.
 6. The system as set forth in claim5, wherein the logic device is further programmed to activate the keyswitch normal indicator and to energize the trouble relays when themaintenance override key switch is switched to the normal position. 7.The system as set forth in claim 5, wherein the logic device is furtherprogrammed to activate the key switch override indicator, activate thenotification beacon, and de-energize the trouble relays when themaintenance override key switch is switched to the maintenance position.8. The system as set forth in claim 5, the logic device being furtherprogrammed to activate the alarm indicator without energizing the alarmequipment relays when the maintenance override key switch is switched tothe maintenance position and upon receipt of the alarm signal; andactivate the discharge indicator without energizing the discharge relayswhen the maintenance override key switch is switched to the maintenanceposition and upon receipt of the discharge signal.
 9. The system as setforth in claim 1, further including a depressible lamp test button and anotification beacon.